Hypothermia is a medical emergency. It occurs when your body gets to dangerously low temperatures, below 35°C. This can be life-threatening. At temperatures this low, your vital organs cannot function properly resulting in organ failure or death as your body fails to retain any heat.
As the body temperature drops, the body begins to shiver to try and create more heat. That will be the first thing you will notice. As the temperature reaches a more dangerous level, your body may become weak, with symptoms of slurred speech, shallow breathing, and drowsiness. It is possible to get symptoms of confusion and losing consciousness. In children, it is important to note - their skin becomes bright red in the cold, unlike the blue colour in adults.
Extreme weather conditions which can happen in other countries and climates or immersion in cold waters such as lakes or rivers are common reasons for hypothermia. It can occur if you stay out in the cold too long, dress inappropriately for the weather, stay in wet clothes too long or live in poor housing conditions. These all lead to situations where your body loses heat faster than it can produce it.
Your age has an effect on your body's ability to regulate temperature. The elderly and the very young have difficulty retaining heat which puts them more at risk. There are also many medical conditions that can lead to hypothermia. Hypothyroidism, diabetes, anorexia nervosa and some neurological conditions impair your body's ability to regulate its temperature. Medications too can have the same effect, such as antidepressants, antipsychotics, and sedative medications. Drugs and alcohol can cause your blood vessels to expand (vasodilate) which means heat is lost from the skin faster. They also impair your reasoning leading you to dress inappropriately for the weather. Passing out in the street when intoxicated from drugs or alcohol puts you at greater risk of hypothermia.
If you think that someone has hypothermia - it is important to call 999 or your local emergency services number immediately. Prolonged exposure to cold water can lead to frostbite (freezing skin cells) or gangrene (dead/decayed cells). Ensure that someone stays with them and remove any wet clothing they may have and replace it with warm dry clothing. If they can move, take them somewhere warm and indoors. If they can eat and drink, give them a warm non-alcoholic drink and something sugary to eat. Keep talking to them until help arrives. Do not, however, rub or shake their body and don't apply any direct heat onto their body. In the hospital, they will be closely monitored and given oxygen if required. They can keep you warm by giving you fluids through the vein. If severe, they may require treatment in intensive care for some time.